1. Field of the Invention
The present invention relates to an inter-wire connection structure for connecting cores of two wires, and a method for manufacturing the same.
2. Description of the Related Art
For example, in a case in which an aluminum wire is used as a wire, since a terminal is made of copper, connection to the terminal corresponds to a dissimilar metal joining. If water permeates a dissimilar metal joining portion, there is a concern about corrosion. Therefore, a corrosion prevention structure for a portion connected to the terminal is needed. The corrosion prevention structure for the portion connected to the terminal requires a change in a shape of the terminal, and a verification of reliability thereof or the like needs to be performed in each case. Therefore, it is very troublesome and incurs high-cost. Hence, there is proposed a structure that connects an end of an aluminum wire to a terminal through a short copper wire.
A related example of an inter-wire connection structure applied to such a structure is illustrated in FIG. 1 (see Japanese Unexamined Patent Application Publication No. 2009-9736). In FIG. 1, an end of an aluminum wire W1 is connected to a short copper wire W2 to which a terminal 140 is connected.
The aluminum wire W1 includes a core 101 and an insulating sheath section 102 sheathing the outer periphery of the core 101. The core 101 is configured by a plurality of twisted element wires 101a. At the end portion of the aluminum wire W1, the insulating sheath section 102 is stripped and the internal core 101 is exposed.
The copper wire W2 includes a core 111 and an insulating sheath section 112 sheathing the outer periphery of the core 111. The core 111 is configured by a plurality of twisted element wires 111a. At the end portion of the copper wire W2, the insulating sheath section 112 is stripped and the internal core 111 is exposed.
The exposed cores 101 and 111 of both the aluminum wire W1 and the copper wire W2 are joined together by ultrasonic welding or the like. Hence, a core joint section 121 is formed. Portions of the exposed cores 101 and 111 of both the aluminum wire W1 and the copper wire W2, and portions of the insulating sheath sections 102 and 112 located at both sides thereof are covered with a heat shrinkable tube 130.
According to the related example, since the connection portion of the terminal 140 is a connection between homogenous metals, corrosion due to water does not occur. Therefore, it is unnecessary to take corrosion prevention measures on the terminal 140.
The portions of connection to the aluminum wire W1 and the copper wire W2 (portions of the cores 101 and 111 exposed from the respective insulating sheath sections 102 and 112) are covered with the tightly-attached heat shrinkable tube 130. Therefore, the permeation of water into the core joint section 121 from the gap between the heat shrinkable tube 130 and the respective insulating sheath sections 102 and 112 may be prevented.